System and Method for Measuring Volume and Pressure

ABSTRACT

A volume measurement system for a fluid processing device includes a fluid container, an imaging unit, and a controller. The container includes a housing defining the structure of the fluid container, and a plurality of fluid chambers. The fluid chambers collect and/or store fluid from the fluid processing device, and each have a port that allows fluid to enter and/or exit the fluid chambers. The imaging unit takes images of the fluid chambers and is positioned to view a level of fluid in each of the chambers. The controller is in communication with the imaging unit and determines the volume of fluid within each of the fluid chambers based upon the viewed level of fluid in the fluid chambers.

PRIORITY

This patent application claims priority from U.S. Provisional PatentApplication No. 62/246,795, filed Oct. 27, 2015, entitled “System andMethod for Measuring Volume and Pressure,” assigned attorney docketnumber 1611/C42, and naming Gary Stacey as inventor, the disclosure ofwhich is incorporated herein, in its entirety by reference.

TECHNICAL FIELD

present invention relates to measuring fluid volumes and pressures, andmore particularly to an imaging system for measuring fluid volumes andpressures.

BACKGROUND ART

During various fluid processing procedures, such as apheresisprocedures, it is important to measure both the volume of fluidscollected/processed, as well as the various pressures throughout thefluid processing system. It is common to measure the volume of fluid ina disposable bag or bottle using a strain gauge load cell. Thistechnique is effective but has several problems. For example, if theload cell or the bag/bottle hanging from the load cell are bumped, themeasurement may be impacted, causing measurement errors. Additionally,if the bump (or other contact) is significant enough to create an overstress on the load cell, the load cell may permanently shift from thezero position, which, in turn, disables the device.

Furthermore, if multiple containers need to weighed, system set up andloading may become labor intensive, as the correct bag/container needsto be hung on the appropriate load cell to avoid errors in measurementand fluid processing. Also, the tubes connected to the bags/containersneed to be positioned in a way that they do not drag on surfaces causingincorrect measurements. Additionally, because each container needs aseparate load cell, the cost increases significantly as additionalcontainers are added to the system.

With respect to pressure measurement, current systems commonly usepressure transducers isolated by a filter to measure pressures withinfluid lines. The filter provides a sterile barrier and prevents fluidand contaminates from touching the transducer. However, any leakage inthe filter/transducer assembly (e.g., between the output of the filterand the transducer) will allow the fluid to contact the filter materialwhich negatively impacts the accuracy of the pressure measurement and,effectively, disables the pressure measurement system. Additionally, ina manner similar to the volume measurement, when multiple pressuremeasurements are needed, system set-up and loading may become laborintensive, and the cost of the system increases significantly (e.g.,because each pressure measurement will require a separate transducer).

SUMMARY OF THE EMBODIMENTS

In accordance with one embodiment of the invention, a volume measurementsystem for a fluid processing device includes a fluid container, animaging unit and a controller. The fluid container may include a fluidcontainer housing that defines the structure of the fluid container, anda plurality of fluid chambers within the fluid container housing. Thefluid chambers may be configured to collect and/or store fluid from thefluid processing device, and each of the fluid chambers may have a portthat allows fluid to enter or exit the fluid chamber. The imaging unitmay take images of the fluid chambers and may be positioned to view alevel of fluid in each of the fluid chambers. The controller may be incommunication with the imaging unit and may determine a volume of fluidwithin each of the fluid chambers based upon the viewed level of fluidin each fluid chamber.

In some embodiments, the system may also include a housing (e.g., asystem housing) that defines the structure of the volume measurementsystem. The imaging unit and controller may be located within thehousing, and at least a portion of a first wall of the system housingmay be transparent to allow the imaging unit to view the fluid containerand take the images. The system/housing may include an opaque cover thatholds the fluid container in place when closed. For example, the fluidcontainer may be located between the opaque cover and the first wallwhen installed in the volume measurement system.

The imaging unit may include a camera that takes the images of theplurality of fluid chambers, and a light source that is directed at thefluid container. The light source may illuminate the fluid chambers toallow the camera to take the images of the fluid chambers. The imagingunit may be a solid state imager and/or include a wide angle lens. Theimaging unit and/or controller may be part of the fluid processingdevice.

The fluid container may also include a plurality of pressure chamberswithin the housing. Each of the pressure chambers may have a chambervolume that is fluidly connectable with a fluid flow line within thefluid processing device. The fluid/pressure within the flow line maycompress the chamber volume when fluidly connected. Each of the pressurechambers may include a tube having an open end and a closed end. Thetube may define the chamber volume, and the chamber volume may befluidly connectable with the fluid flow line via the open end. The innerdiameter of the tube may be dependent on a target pressure range for thepressure chamber. Additionally, the imaging unit may take images of theplurality of pressure chambers, and the controller may determine apressure level within the pressure chambers based on the image of thepressure chambers. The controller may use a look-up table to determinethe pressure level and/or volume of fluid.

The housing of the fluid container may include a first and second sheetof flexible material that are secured together to form the fluidchambers and/or the pressure chambers. For example the first and secondsheets of material may be PVC and RF welded together. Additionally oralternatively, the housing may have a plurality of reference marks oneach of the fluid chambers that provide an indication of a fluid levelin each of the fluid chambers. In such embodiments, the fluid level maybe related to the volume of fluid within the fluid chamber. The fluidcontainer may have perforations that allow the fluid chambers and/orpressure chambers to be separated from one another. One or more of thefluid chambers may be V-shaped.

In accordance with additional embodiments, a method of measuring avolume of fluid within a fluid container may include providing a fluidcontainer having a plurality of fluid chambers and fluidly connectingeach of the fluid chambers to a fluid line on the fluid processingsystem via a port on the fluid chambers. The fluid container may alsoinclude a fluid container housing defining the structure of the fluidcontainer. The fluid chambers may be within the housing and configuredto collect and/or store fluid from the fluid processing system. Theports may allow fluid to enter or exit each of the fluid chambers. Themethod may also include installing the fluid container into a volumemeasurement device. The volume measurement device may have an imagingunit that takes images of the fluid chambers and is positioned to view alevel of fluid in each of the fluid chambers. The method may then imageeach of the fluid chambers using the imaging unit, and determine, usinga controller in communication with the imaging unit, a volume of fluidwithin each of the fluid chambers based upon the images of the fluidchambers.

The volume measurement device may include a system housing defining thestructure of the volume measurement device. The imaging unit andcontroller may be located within the housing, and at least a portion ofa first wall of the system housing may be clear to allow the imagingunit to view the fluid container and take the images. The system housingmay also have an opaque cover, and installing the fluid container intothe volume measurement device may include closing the opaque cover overthe fluid container to secure the fluid container within the volumemeasurement device.

The imaging unit may include (1) a camera configured to take the imagesof the fluid chambers, and (2) a light source directed at the fluidcontainer and configured to illuminate the fluid chambers to allow thecamera to take the images of the fluid chambers. The imaging unit may bea solid state imager and/or include a wide angle lens. The volumemeasurement device may be part of the fluid processing system.

In some embodiments, the fluid container may include a plurality ofpressure chambers within the housing and having chamber volumes. In suchembodiments, the method may include fluidly connecting each of thepressure chambers to a fluid flow line within the fluid processingsystem, such that a pressure/fluid within the flow line compresses thechamber volume. Additionally, the method may image each of the pressurechambers using the imaging unit, and determine, using the controller, apressure level within each of the pressure chambers based on the imageof the pressure chamber.

Each of the pressure chambers may include a tube with an open end and aclosed end. The tube may define the chamber volume, and the chambervolume may be in fluid communication with the fluid flow line via theopen end. The inner diameter of the tube may be dependent on a targetpressure range for the pressure chamber. The controller may use alook-up table to determine the pressure level within each of thepressure chambers.

The fluid container housing may include a first sheet and second sheetof flexible material (e.g., PVC) that are secured together (e.g., via RFwelding) to form the plurality of fluid chambers and/or pressurechambers. The housing may have plurality of reference marks on each ofthe fluid chambers that provide an indication of the fluid level in eachof the fluid chambers. The fluid level may be related to a volume offluid within the fluid chamber.

In accordance with still further embodiments, a fluid container for afluid processing system includes a housing defining the structure of thefluid container, a plurality of fluid chambers within the housing, and aplurality of pressure chambers within the housing. The fluid chambersmay collect and/or store fluid from the fluid processing system, andeach fluid chamber may have a port that allows fluid to enter or exiteach of the fluid chambers. Each of the pressure chambers may have achamber volume and may be fluidly connectable with a fluid flow linewithin the fluid processing system, such that a pressure/fluid withinthe flow line compresses the chamber volume when fluidly connected.Additionally or alternatively, each of the pressure chambers may have atube with an open end and a closed end. The tube(s) may define thechamber volume, and the chamber volume may be in fluid communicationwith the fluid flow line via the open end. The inner diameter of thetube may be dependent on a target pressure range for the pressurechamber.

The housing may include a first and second sheet of flexible material(e.g. PVC) that are secured together (e.g., via RF welding) to form theplurality of fluid chambers and plurality of pressure chambers. Thehousing may also include reference marks on each of the fluid chambers.The reference marks may provide an indication of a fluid level in eachof the fluid chambers. The fluid level in each of the fluid chambers maybe related to a volume of fluid within the fluid chamber. One or more ofthe fluid chambers may be V-shaped.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing features of embodiments will be more readily understood byreference to the following detailed description, taken with reference tothe accompanying drawings, in which:

FIG. 1 schematically shows a cross-sectional view of a fluid bag inaccordance with embodiments of the present invention.

FIG. 2 schematically shows a volume and pressure measurement system withthe fluid bag of FIG. 1 installed, in accordance with embodiments of thepresent invention.

FIG. 3 schematically shows an exemplary disposable set containing afluid container similar to that shown in FIG. 1 and for use with thevolume and pressure measurement system shown in FIG. 2, in accordancewith embodiments of the present invention.

FIG. 4 schematically shows an exemplary layout of a blood processingsystem for use with the volume and pressure measurement system shown inFIG. 2, in accordance with embodiments of the present invention.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

In illustrative embodiments, a volume and pressure measurement system isable to measure a volume of fluid within a fluid container by taking animage of the fluid container. Additionally, various embodiments are ableto measure a pressure within a pressure chamber by similarly taking animage of the pressure chamber. The pressure may correspond to a pressurewithin a fluid line of a fluid processing system to which the fluidcontainer is connected.

FIG. 1 schematically shows a cross section of a fluid container 100 foruse with the volume and pressure measurement system, in accordance withembodiments of the present invention. The fluid container 100 has ahousing 110 that defines the structure of the container 100. The housing110 may be constructed from two sheets of PVC material that are securedto one another (e.g., via RF welding) to form the container. In thismanner, the container may be constructed in a manner similar to adisposable fluid or blood bag used with an apheresis and other bloodprocessing system.

To allow the container 100 to collect and/or store more than one type offluid, the container 100 may contain a number of fluid chambers/bags120A-D. Each of these chambers/bags 120A-D may have at least one port130A-D (e.g., an inlet, an outlet, or an inlet and an outlet) to allowfluid to be collected within or withdrawn from the chamber 120A-D(discussed in greater detail below). In use, each of the ports 130A-Dmay be fluidly connected to a fluid processing system. For example, ifthe fluid processing system is a blood processing system (e.g., anapheresis system), the ports 130A-D may be fluidly connected to a bloodcomponent separation device within the blood processing system and/or toone or more fluid transfer lines. As discussed in greater detail below,when fluidly connected in this manner, some of the fluid chambers 120A-Dmay be used to collect processed fluids/blood components (e.g., plasma,platelets, etc.). To improve the low volume accuracy, one or more of thefluid chambers 120A-D may be V-shaped so that the fluid level within thechamber 120A-D increases more significantly when only small volume offluid is within the chamber 120A-D (e.g., such that a small increase influid volume significantly increases the height of the fluid level).

In addition to the fluid chambers 120A-D, as shown in FIG. 1, someembodiments of the fluid container 100 may also contain one or morepressure chambers 140A-C that, as discussed in greater detail below, maybe used to measure the pressure within one or more of the fluid lines ofthe fluid processing system. Like the fluid chambers/bags 120A-D, eachof the pressure chambers 140A-C may have a port 150A-C that, in turn,can be fluidly connected to the fluid processing system. For example,each port 150A-C of the pressure chambers 140A-C may be fluidlyconnected (e.g., via a section of tubing and a connector) to a fluidline within the fluid processing device.

As noted above, the pressure chambers 140A-C may be used to measure thepressure within the lines of the fluid processing system (e.g. thepressure within the line to which the individual pressure chamber 140A-Cis fluidly connected). To that end, the pressure chambers 140A-C maycontain a volume of air that compresses as the pressure within thefluidly connected line increases, and expands as the pressure decreases.For example, as fluid flows through the lines of the fluid processingsystem, a small volume of fluid will flow into the line connecting thepressure chamber 140A-C and the fluid processing device and into thepressure chamber 140A-C. As the pressure within the fluid line increasesand decreases, the fluid level within the pressure chamber 140A-C (e.g.,from the small volume of fluid that flows in) will similarly go up anddown. The volume and pressure measurement system may then monitor thefluid level within each pressure chamber 140A-C to determine thepressure within the fluid line (discussed in greater detail below).

It should be noted that, depending on the material used to form thecontainer 100, the container 100 material may be too pliable to allowfor accurate pressure measurement (e.g., it may deform as the pressureincreases). Therefore, in some embodiments, the pressure chamber 140A-Cmay include a section of semi-rigid tubing (not shown) that extends thelength of the pressure chamber 140A-C and defines the volume of air(e.g., the internal diameter of the tubing may define the volume ofair). In such embodiments, the tubing may be RF welded within thepressure chamber 140A-C and may have a closed/sealed top end and an openopposing/bottom end (e.g., to allow the fluid to enter the pressurechamber 140A-C). The open end of the tubing may form the port 150A-Cthat is fluidly connected to the fluid processing system. Alternatively,the port 150A-C may be connected/secured to the open end of the tubing.

In some embodiments, it may be necessary to measure pressures across avariety of ranges (e.g., the required pressure range for one pressurechamber 140A-C may be greater/less than the required pressure range foranother pressure chamber 140A-C). To accommodate varying pressureranges, the size of the pressure chamber 140A-C and/or the semi-rigidtubing may be adjusted up or down. For example, if the required pressurerange/scale is relatively large (e.g., the pressure within the fluidline is relatively high), tubing having a larger inner diameter may beused (to create a larger volume of air). Conversely, if the pressurerange/scale is relatively low (e.g., the pressure within the fluid lineis low), tubing having a smaller inner diameter (to create a smallervolume of air) may be used. Additionally, the length of the tubing(e.g., the height of the pressure chamber 140A-C) may be adjusted to getthe desired pressure level and sensitivity (e.g., the length of thesemi-rigid tube may be increased to increase the pressure range ordecreased to reduce the pressure range).

In some applications, it may be necessary or desirable to separate theindividual fluid chambers 120A-D from one another and from the pressurechambers 140A-C (and separate the pressure chambers 140A-C from oneanother). To that end, some embodiments of the fluid container mayinclude perforations that separate each of the fluid chambers 120A-Dfrom one another, and from each of the pressure chambers 140A-C. Thisallows the user to remove individual fluid chambers 120A-D as needed(e.g., after fluid processing). It should also be noted that, althoughFIG. 1 shows a fluid container 100 having three pressure chambers 140A-Cand four fluid chambers 120A-D, other embodiments may have more or lesspressure chambers 140A-C and fluid chambers 120A-C (e.g., depending onthe application/fluid processing procedure). For example, the fluidcontainer 100 have less than three (e.g., from 0-2) or more than three(4 or more) pressure chambers 140A-C. Similarly, the fluid container 100may have less than four fluid chambers 120A-D (e.g., from 0-3) or morethan four fluid chambers 120A-D (5 or more).

As noted above, the fluid container 100 can be used in conjunction witha fluid volume and pressure measurement system 200 that is capable ofdetermining the volume of fluid within each fluid chamber 120A-D and thepressure within the pressure chambers 140A-C (if the container 100includes pressure chambers 140A-C). As shown in FIG. 2, the measurementsystem 200 may include a housing 210 in which the components of thesystem 200 may be located. The housing 200 may also include ameasurement area 220 in which the container 100 may be placed duringmeasurement and a cover 230 that holds the container 100 in place. Thecover 230 may be secured to the housing 210 via a hinge to allow thecover 230 to open and close and the container 100 to be placed in themeasurement area 220. Alternatively, the cover 230 may be stationarywith respect to the housing 210 and may include a slot 235 through whichthe container 100 may be inserted into the measurement area 220. Asdiscussed in greater detail below, the wall 212 of the housing 210 atthe measurement area 220 may be clear/transparent and the cover 230 maybe opaque.

In order to measure the volumes and pressures, the system 200 includesan imaging unit 240 that takes images of the container 100 through theclear wall 212 of the housing 210 when the container 100 is within themeasurement area 220. To that end, the imaging unit 240 may include asolid state imager 242 with one or more cameras aimed through the clearwall 212 into the measurement area 220. Additionally, in someembodiments, the imaging unit 240 may include a light source 244 thatilluminates the container 100 to allow the imaging unit 240 to image thecontainer 100.

The light source 244 may include one or more light emitting diodes(LEDs) that illuminate the container 100. In some embodiments, the lightsource 244 may include an array of LEDS having varying colors (e.g.,red, green, blue, etc.) to allow the imaging system 200 to illuminatethe container 100 in a number of colors. In order to minimize thesetback distance (e.g., the distance between the container 100 and theimaging unit 240) and the size of the system 200, the imaging unit(e.g., the solid state imager 242/camera) may have a wide angle lens.

During use, the imaging unit 240 may image the container 100 and sendthe images and/or image data to a controller 250, which determines thefluid volume and/or pressure based on the image/image data. For example,with respect to the fluid volume, the controller 250 may determine thevolume of fluid within each of the fluid chambers 120A-D based on thefluid level within the respective fluid chamber 120A-D. To aid indetermining the fluid level within each of the fluid chambers 120A-D,the container 100 may include a series of reference marks/graduations.For example, the container 100 may include one set of reference marksfor the entire container 100 (e.g., all fluid chambers 120A-D mayutilize the same set of marks), or each fluid chamber 120A-D may havetheir own set of reference marks. In addition to providing a moreaccurate measure of the fluid level within the fluid chambers 120A-D,the reference marks also allow the system 200 to automatically adjustand eliminate sensor (e.g., solid state imager 242) calibration.

With respect to the pressure chambers 140A-C, the system 200 may measurethe pressure by monitoring the fluid level within the pressure chamber140A-C. As mentioned above, each of the pressure chambers 140-C may befluidly connected to a fluid line in a fluid processing system. In sucha configuration, a portion of fluid flowing through the fluid lineconnected to the pressure chamber 140A-C will flow into the pressurechamber 140A-C and will compress the volume of air within the pressurechamber 140A-C. The amount of compression (and, therefore, the fluidlevel within the pressure chamber 140A-C) is directly related to thepressure within the fluid line. For example, if the pressure within thefluid line increases, the fluid will further compress the volume of airin the pressure chamber 140A-C and the fluid level will rise.Conversely, if the pressure within the fluid line drops, the amount ofcompression will decrease (e.g., the volume of air will expand) and thefluid level will drop. Like with the fluid chambers 120A-D, thecontroller 150 may then determine the pressure of the fluid within thefluid line based on the fluid level within the pressure chamber 140A-C.In some embodiments, like the fluid chambers 120A-D, the pressurechambers 140A-C may include reference marks/graduations to improve theaccuracy of the level measurement.

In order to aid in the calculation/determination of the volume and/orpressure, some embodiments of the present invention may utilize look-uptables that correlate the imaged fluid level (e.g., the level of thefluid within the fluid chambers 120A-D and/or the level of fluid withinthe pressure chambers 140A-C) with a fluid volume in the fluid chamber120A-D or pressure within the fluid line. For example, for a givencontainer 100 (and/or for a given fluid processing system), the system200 (e.g., the controller 250) may determine the level of fluid for agiven chamber (e.g., using the reference marks) and then refer to thelook-up table to find the fluid volume or pressure that correlates tothe imaged fluid level.

Once the system 200/controller 250 has determined the fluid volumeand/or pressures, the system 200 may display the volume and/or pressureon a display on the system. Additionally or alternatively, the system200 can send the volume and pressure information to the fluid processingsystem for display and/or use by the fluid processing system. In someembodiments the system 200 (or the fluid processing system) may monitorthe fluid volume and/or pressure to determine if the fluid volumereaches a target or threshold level. For example, if the fluid levelwithin one of the fluid chambers 120A-D reaches a target level (e.g.,indicating that a target volume of fluid has been collected in the fluidchamber 120A-D), the system 200 or the fluid processing system may stopor otherwise alter the fluid processing procedure. Similarly, if thepressure within one or more of the pressure chambers 140A-C goes aboveor below a threshold level (e.g., indicating that a pressure in one ofthe fluid lines is too high or too low), the system 200 may initiate analarm or adjust the fluid flow within the fluid line.

FIG. 3 schematically shows a disposable set for a blood processingdevice utilizing a fluid container 100 and system 200 similar to thatdescribed above. It is important to note that, unlike the container 100shown in FIG. 1 (which has three pressure chambers 140A-C and four fluidchambers 120A-D), the container 100 shown in FIG. 3 has five fluidchambers 120A-E and no pressure chambers 140A-C. Also, although FIG. 3shows the fluid container 100 being used for blood processing, thecontainer 100 can be used for any number of liquid processingprocedures.

During blood processing, whole blood may be drawn from a source (e.g., apatient, a blood storage bag, etc.) using a donor/draw pump 330, andthrough a draw line 310. In some embodiments, a portion of the drawnwhole blood may flow into the centrifuge bowl 320 and a portion of thewhole blood may be diverted to an in-buffer/draw chamber 120A.Alternatively, all of the whole blood may be diverted to thein-buffer/draw chamber 120A and later drawn from the in-buffer/drawchamber 120A and into the bowl 320. Also, while the whole blood is beingdrawn from the source, an anticoagulant pump 340 may draw anticoagulantthrough an anticoagulant line 342 and filter 344 from an anticoagulantsource 345. The anticoagulant may mix with the drawn whole blood priorto reaching the in-buffer/draw chamber 120A and/or the bowl 320. To makeroom for the whole blood entering the bowl 320, the air within the bowl320 may be displaced via an outlet 322 and line 370 to an air chamber120C of the container 100.

Once the initial draw step has commenced and a sufficient amount ofanticoagulated whole blood is collected in the in-buffer/draw chamber120A, a bowl pump 350 may begin to draw anticoagulated whole blood fromthe in-buffer/draw chamber 120A via line 352. As the bowl pump 350 drawsthe anticoagulated whole blood from the in-buffer/draw chamber 120A,valves (not shown) may be opened to allow the anticoagulated whole bloodto flow into line 352. In order to ensure that a sufficient volume ofanticoagulated whole blood remains within the in-buffer/draw chamber120A (e.g., to maintain a continuous flow of anticoagulated whole bloodto the bowl 320), the bowl pump 350 may draw the anticoagulated wholeblood from the in-buffer/draw chamber 120A at a rate slower than that ofthe donor pump 330. For example, the bowl pump 350 may draw at a rate of60 mL/min as compared to the donor pump's rate of 120 mL/min. The bowl320 will continue to fill until an optical system 360 detects thepresence of a plasma/cell interface created by the separation of thewhole blood within the bowl 320.

As additional anticoagulated whole blood is introduced into the bowl320, the whole blood will continue to separate. For example, thecentrifugal forces cause the heavier cellular components of the blood tosediment from the lighter plasma component of the blood. This results inthe cell/plasma interface mentioned above. The red blood cells are byfar the most numerous of the cellular components of blood and the mostdense, resulting in a layer of concentrated red blood cells at theoutermost diameter of the bowl 320. As filling continues, the othercellular components of blood begin to become apparent. These cellularcomponents are primarily platelets, leukocytes and peripheralhematopoietic progenitor stem cells. These cells may have a range ofdensities between that of the red blood cells and plasma. Therefore theytend to sediment in a layer between the red blood cell layer and plasmalayer. As this layer grows, it is visually apparent as a solid whitelayer which is known as a buffy coat.

As the bowl 320 continues to fill with whole blood, the red blood cellswill continue to sediment to the outermost diameter, and theintermediate cells of the buffy coat will continue to accumulate at thered blood cell/plasma interface, and the plasma interface will moveinward towards the center of the bowl 320. When the bowl 320 is full,the plasma will exit the bowl 320 via the outlet 322. As the plasmaexits the bowl 320, some of the plasma may pass through line 370 andinto an out buffer chamber 120E of the container 100 and some of theplasma may be sequestered within the plasma chamber 120B of thecontainer 100. To sequester this plasma in the plasma chamber 120B, theoperator or the control system of the blood processing system can openvalve C3 to allow some of the plasma exiting the bowl 320 to enter line372 and flow into the plasma chamber 120B. The sequestered plasma in theplasma chamber 120B may be used during a surge elutriation procedure toremove the platelets from the bowl 320.

In some embodiments, the bowl 320 may be a continuous flow bowl thatallows the continuous processing of whole blood without the need tointermittently stop. To that end, various embodiments of the presentinvention also extract red blood cells from the bowl 320 as additionalwhole blood is introduced (e.g., while simultaneously extractingplasma). For example, once the red blood cells have collected within thebowl 320, a red blood cell pump 380 can draw red blood cells out of anadditional output 324 (e.g., a first blood component/red blood celloutlet) on the bowl 320. As the red blood cells leave the bowl 320, theywill pass through line 385 and into the out buffer chamber 120E (e.g.,which acts as a return chamber). While the red blood cell pump 380extracts the red blood cells, the optical system 360 will monitor thelocation of the plasma/cell interface and may control the flow rate ofthe red blood cell pump 380 to adjust the location of the interface asnecessary (e.g., it will speed up the pump 380 if the sensor outputdecreases and slow down the pump 380 if the sensor output increases).

Once the donor pump 330 has drawn a predetermined volume of whole bloodfrom the source, the system 300 will stop the draw step and begin toreturn some of the blood components (e.g., red blood cells and plasma)that have been collected in the out buffer/return chamber 120E. Forexample, the system 300 may energize a return pump 390, which will draw(e.g., at 120 mL/min) the plasma and red blood cells within the outbuffer/return chamber 120E through line 395, and back to the source(e.g., back to the patient). This return phase will continue until apredetermined volume of red blood cells and plasma are returned to thesubject, for example, 80 mL. The system 300 may then alternate the drawand return phases until the procedure is complete. In some embodiments,a compensation fluid such as saline may be returned to the patient alongwith the blood components within the out buffer/return chamber 120E. Insuch embodiments, the return pump 390 may draw the compensation fluidfrom a container 440 and through a compensation line 445.

In continuous systems like that shown in FIG. 3, anticoagulated wholeblood may be continuously drawn from the in-buffer/draw chamber 120A andinto the bowl 320, even during the return phase. As mentioned above,this can be accomplished by first drawing a bolus volume of whole bloodfrom the subject, collecting the bolus volume of whole blood within thein-buffer/draw chamber 120A, and drawing the whole blood from thein-buffer/draw chamber 120A at a slower rate than the draw and returnsteps (e.g., the bowl pump 350 draws the anticoagulated whole blood at60 mL/min and the donor pump 330 draws the whole blood from the subjectand returns the red blood cells and plasma to the subject at 120mL/min). Therefore, the in-buffer/draw chamber 120A always has asufficient volume of anticoagulated whole blood from which the bowl pump350 can draw.

The whole blood processing may continue until a desired volume ofplatelets has accumulated within the bowl 320. When the blood processingis complete, the system 300 may then perform a surge elutriation processusing the sequestered plasma in order to extract the highly concentratedplatelet product. For example, the bowl pump 350 can draw the plasmawithin the plasma chamber 120B through a plasma recirculation line 354and into the bowl 320 (e.g., via the inlet 326). To elutriate theplatelets, the flow rate of plasma is gradually increased. As the flowrate is increased, the effluent plasma passes through a line sensor 374(located on line 370) that monitors the fluid exiting the bowl 320. Atsome point in this ramping up of plasma flow rate, the drag forcecreated by the plasma flow overcomes the centrifugal force caused by thebowl rotation, and the platelets are carried away from the buffy coat inthe flowing plasma. The line sensor 374 may then detect the presence ofcells (e.g., as the fluid exiting the bowl 320 changes from plasma toplatelets), and the system 300 (or the user) can close valve C3 and openvalve C5 to allow the platelets to flow into the platelet line 376 andinto the platelet chamber 120D of the container 100.

After the elutriation process and after the platelets are collectedwithin the platelet chamber 120D, the system 300 may stop the bowl 320and return the contents of the bowl 320 to the donor. For example, thesystem 300 may turn on the red blood cell pump 380 to draw the contentsof the bowl 320 into the out buffer/return chamber 120E (via line 385).The return pump 390 may then draw the contents of the out buffer/returnchamber 120E through line 395, and return the components via the returnline 397. Additionally, in some applications, platelet additive solutionmay be added to the platelets within the platelet chamber 120D (fromplatelet additive solution container 430 and via line 435 and valve C6),and the platelets may be filtered using a platelet filter 410 andtransferred to a filtered platelet container 420 via line 415.

Throughout the blood processing procedure, the vision system 200 canmonitor the fluid levels in each of the chambers 120A-E in mannersimilar to that described above. For example, as the plasma enters or isdrawn from the plasma chamber 120B, platelets enter/are drawn from theplatelets chamber 120D, and when plasma and/or red blood cells enter/aredrawn from the out buffer/return chamber 120E, the vision system 200 canmonitor the volumes collected and/or remaining in each of the chambers120A-E. Additionally, the vision system 200 may monitor the level ofwhole blood within the in-buffer/draw chamber 120A to ensure that thein-buffer/draw chamber 120A contains sufficient whole blood tocontinuously supply the bowl 320 with whole blood. The blood processingsystem 300 may then use this information to adjust/alter/control theblood processing procedure. For example, the blood processing system 300can control the pumps, centrifuge bowl 320, valves, or other componentsof the system based upon the volumes.

Although FIG. 3 illustrates a blood processing system 300 utilizing acontainer 100 without pressure chambers, as noted above, otherembodiments may include pressure chambers to allow the vision system 200and/or the blood processing system to measure the pressures within oneor more of the fluid lines. For example, FIG. 4 shows a layout of theblood processing system 300 with a container 100 with five fluidchambers 120A-E (like the container shown in FIG. 3), and three pressurechambers 140A-C. It should be noted that the operation of the bloodprocessing system 300 is similar to that shown in FIG. 3 (including theroles of each of the fluid chambers 120A-E) and described above.

As shown in FIG. 4, an anticoagulant pressure chamber 140A may connectto the anticoagulant line 342 at pressure connection 346. Similarly, adraw pressure chamber 140B may connect to the draw line 310 at pressureconnection 315, and a seal pressure chamber 140C may connect to line 370extending from outlet 322 at pressure connection 375 (see FIG. 3). Itshould be noted that, although the embodiment shown in FIG. 4 does notinclude a pressure chamber connected to the red blood cell pressureconnection 387 (e.g., it uses a standard pressure transducer to measurethe pressure within the red blood cell line 385), other embodiments caninclude a fourth pressure chamber that is connected to the red bloodcell line 385 at pressure connection 387.

During blood processing, a portion of the fluid in each of the fluidlines (e.g., the anticoagulant line 342, the draw line 310, and line370) will enter the pressure chambers 140A-C and cause the volume of airwithin each of the chambers 140A-C to compress. Then, as the pressurewithin each of the lines 310/341/370 changes, the pressure change willbe translated to the pressure chambers 140A-C, causing the volume of airin the chambers 140A-C to compress further if the pressure increasesand/or expand if the pressure decreases (e.g., the fluid level withinthe chambers 140A-C will move up and/or down). The vision system 200 maythen monitor the fluid level within each of the chambers 140A-C anddetermine the respective pressure within the connected line (e.g.,within lines 342, 310 and 370). The system 200 may then send thispressure information to the blood processing system 300 (e.g., to acontroller within the blood processing system 300) along with the fluidvolume information determined from the fluid chambers 120A-E. The bloodprocessing system 300 may then adjust/alter/control the blood processingprocedure. For example, the blood processing system 300 can control thepumps, centrifuge bowl 320, valves, or other components of the systembased upon the measured pressures (and/or volumes).

It should be noted that, although the blood processing method discussedabove draws whole blood from and returns the contents of the bowl to adonor, some embodiments may not draw from and/or return to a donor.Rather, in some embodiments, the whole blood may be drawn from a wholeblood storage container, and the contents of the bowl 320 may bereturned to the whole blood storage container (or a different bloodstorage container).

It is important to note that, in addition to providing an accuratevolume and pressure measurement, embodiments of the present inventionprovide additional benefits over prior art containers andpressure/volume measurement system. For example, because the container100 includes individual chambers 120A-D for a number of fluids collectedand used during fluid processing, the container 100 may be installed asa single piece as opposed to several separate containers. This, in turn,simplifies installation/loading and reduces installation/loading time.Additionally, by adding additional chambers to the container 100,embodiments of the present invention are able to further reduce thecomplexity of the fluid processing system (e.g., the blood processingsystem 300), system calibration, and cost, while increasing reliability.

The embodiments of the invention described above are intended to bemerely exemplary; numerous variations and modifications will be apparentto those skilled in the art. All such variations and modifications areintended to be within the scope of the present invention as defined inany appended claims.

What is claimed is:
 1. A volume measurement system for a fluidprocessing device comprising: a fluid container including: a fluidcontainer housing defining the structure of the fluid container; aplurality of fluid chambers within the fluid container housing andconfigured to collect and/or store fluid from the fluid processingdevice, each of the plurality of fluid chambers having a port configuredto allow fluid to enter or exit each of the fluid chambers; an imagingunit configured to take images of the plurality of fluid chambers andpositioned to view a level of fluid in each of the plurality of fluidchambers; and a controller in communication with the imaging unit andconfigured to determine a volume of fluid within each of the pluralityof fluid chambers based upon the viewed level of fluid in each of theplurality of fluid chambers
 2. A system according to claim 1, furthercomprising: a system housing defining the structure of the volumemeasurement system, the imaging unit and controller located within thehousing, at least a portion of a first wall of the system housing beingtransparent to allow the imaging unit to view the fluid container andtake the images.
 3. A system according to claim 2, further comprising anopaque cover, the fluid container located between the opaque cover andthe first wall when installed in the volume measurement system.
 4. Asystem according to claim 3, wherein the opaque cover holds the fluidcontainer in place when closed.
 5. A system according to claim 1,wherein the imaging unit includes: a camera configured to take theimages of the plurality of fluid chambers; and a light source directedat the fluid container and configured to illuminate the plurality offluid chambers, thereby allowing the camera to take the images of theplurality of fluid chambers.
 6. A system according to claim 1, whereinthe controller is part of the fluid processing system.
 7. A systemaccording to claim 1, wherein the imaging unit is a solid state imager.8. A system according to claim 1, wherein the imaging unit includes awide angle lens.
 9. A system according to claim 1, wherein the imagingunit and controller are part of the fluid processing device.
 10. Asystem according to claim 1, wherein the fluid container furtherincludes a plurality of pressure chambers within the fluid containerhousing, each of the pressure chambers having a chamber volume that isfluidly connectable with a fluid flow line within the fluid processingdevice, a pressure within the fluid flow line configured to compress thechamber volume when fluidly connected.
 11. A system according to claim10, wherein each of the plurality of pressure chambers includes a tubehaving an open end and a closed end and defining the chamber volume, thechamber volume fluidly connectable with the fluid flow line via the openend.
 12. A system according to claim 11, wherein an inner diameter ofthe tube is dependent on a target pressure range for the pressurechamber.
 13. A system according to claim 10, wherein the imaging unit isfurther configured to take images of the plurality of pressure chambers,the controller further configured to determine a pressure level withineach of the plurality of pressure chambers based on the image of thepressure chambers.
 14. A system according to claim 13, wherein thecontroller uses a look-up table to determine the pressure level withineach of the plurality of pressure chambers.
 15. A system according toclaim 1, wherein the fluid container housing includes: a first sheet offlexible material; and a second sheet of flexible material, the firstsheet of flexible material being secured to the second sheet of flexiblematerial to form the plurality of fluid chambers.
 16. A system accordingto claim 15, wherein the first and second sheets of flexible materialare PVC.
 17. A system according to claim 1, wherein the housing includesa plurality of reference marks on each of the fluid chambers, thereference marks providing an indication of a fluid level in each of thefluid chambers.
 18. A system according to claim 17, wherein the fluidlevel is related to a volume of fluid within the fluid chamber.
 19. Asystem according to claim 1, wherein the controller uses a look-up tableto determine the volume of fluid within each of the plurality of fluidchambers.
 20. A system according to claim 1, wherein the fluid containerincludes perforations configured to allow the fluid chambers to beseparated from one another.
 21. A system according to claim 1, whereinat least one of the plurality of fluid chambers is V-shaped.
 22. Amethod of measuring a volume of fluid within a fluid containercomprising: providing a fluid container, the fluid container comprising:a fluid container housing defining the structure of the fluid container;a plurality of fluid chambers within the fluid container housing andconfigured to collect and/or store fluid from the fluid processingsystem, each of the plurality of fluid chambers having a port configuredto allow fluid to enter or exit each of the fluid chambers; fluidlyconnecting each of the plurality of fluid chambers to a fluid line onthe fluid processing system via the port; installing the fluid containerinto a volume measurement device, the volume measurement device havingan imaging unit configured to take images of the plurality of fluidchambers and positioned to view a level of fluid in each of theplurality of fluid chambers; imaging each of the plurality of fluidchambers using the imaging unit; and determining, using a controller incommunication with the imaging unit, a volume of fluid within each ofthe plurality of fluid chambers based upon the images of the fluidchambers.
 23. A method according to claim 22, wherein the volumemeasurement device includes a system housing defining the structure ofthe volume measurement device, the imaging unit and controller locatedwithin the housing, at least a portion of a first wall of the systemhousing being clear to allow the imaging unit to view the fluidcontainer and take the images.
 24. A method according to claim 23, thesystem housing further comprising an opaque cover, wherein installingthe fluid container into the volume measurement device includes closingthe opaque cover over the fluid container to secure the fluid containerwithin the volume measurement device.
 25. A method according to claim22, wherein the imaging unit includes: a camera configured to take theimages of the plurality of fluid chambers; and a light source directedat the fluid container and configured to illuminate the plurality offluid chambers, thereby allowing camera to take the images of theplurality of fluid chambers.
 26. A method according to claim 22, whereinthe imaging unit is a solid state imager.
 27. A method according toclaim 22, wherein the imaging unit includes a wide angle lens.
 28. Amethod according to claim 22, wherein the volume measurement device ispart of the fluid processing system.
 29. A method according to claim 22,wherein the fluid container further includes a plurality of pressurechambers within the housing and having chamber volumes.
 30. A methodaccording to claim 29, further comprising: fluidly connecting each ofthe pressure chambers to a fluid flow line within the fluid processingsystem, a pressure within the fluid flow line configured to compress thechamber volume.
 31. A method according to claim 30, further comprising:imaging each of the plurality of pressure chambers using the imagingunit; determining, using the controller, a pressure level within each ofthe plurality of pressure chambers based on an image of the pressurechambers.
 32. A method according to claim 31, wherein each of theplurality of pressure chambers includes a tube having an open end and aclosed end, the tube defining the chamber volume, the chamber volume influid communication with the fluid flow line via the open end.
 33. Amethod according to claim 32, wherein an inner diameter of the tube isdependent on a target pressure range for the pressure chamber.
 34. Amethod according to claim 31, wherein the controller uses a look-uptable to determine the pressure level within each of the plurality ofpressure chambers.
 35. A method according to claim 22, wherein the fluidcontainer housing includes: a first sheet of flexible material; and asecond sheet of flexible material, the first sheet of flexible materialbeing secured to the second sheet of flexible material to form theplurality of fluid chambers.
 36. A method according to claim 35, whereinthe first and second sheets of flexible material are PVC.
 37. A methodaccording to claim 22, wherein the housing includes a plurality ofreference marks on each of the fluid chambers, the reference marksproviding an indication of a fluid level in each of the fluid chambers.38. A method according to claim 37, wherein the fluid level is relatedto a volume of fluid within the fluid chamber.
 39. A fluid container fora fluid processing system comprising: a housing defining the structureof the fluid container; a plurality of fluid chambers within the housingand configured to collect and/or store fluid from the fluid processingsystem, each of the plurality of fluid chambers having a port configuredto allow fluid to enter or exit each of the fluid chambers; and aplurality of pressure chambers within the housing, each of the pressurechambers having a chamber volume fluidly connectable with a fluid flowline within the fluid processing system, a pressure within the fluidflow line compressing the chamber volume when fluidly connected.
 40. Afluid container according to claim 39, wherein each of the plurality ofpressure chambers includes a tube having an open end and a closed endand defining the chamber volume, the chamber volume in fluidcommunication with the fluid flow line via the open end.
 41. A fluidcontainer according to claim 40, wherein an inner diameter of the tubeis dependent on a target pressure range for the pressure chamber.
 42. Afluid container according to claim 39, wherein the housing includes: afirst sheet of flexible material; and a second sheet of flexiblematerial, the first sheet of flexible material begin secured to thesecond sheet of flexible material to form the plurality of fluidchambers and plurality of pressure chambers.
 43. A fluid containeraccording to claim 42, wherein the first and second sheets of flexiblematerial are PVC.
 44. A fluid container according to claim 39, whereinthe housing includes a plurality of reference marks on each of the fluidchambers, the reference marks providing an indication of a fluid levelin each of the fluid chambers.
 45. A fluid container according to claim44, wherein the fluid level in each of the plurality of fluid chambersis related to a volume of fluid within the fluid chamber.
 46. A fluidcontainer according to claim 39, wherein at least one of plurality offluid chambers is V-shaped.